I would add Erlang and node.js to the list. I need to build a HTTP server for frequent polling for a project that I am working on (polling or websockets if available, lots of users) and I narrowed down building that component in either Erlang, node.js or Python.

I have really taken a liking to the Erlang model. Processes share no memory and communicate by passing messages. There is no shared state locking/mutex.

Once I have more data/information (benchmarks, ease of development/integration etc.) I will publish my results.